Identity matching systems have been used in a range of settings to control access to secure locations, protect information against security breaches, and to detect individuals who pose a threat to public safety. For example, the National Crime Information Center (NCIC) provides a database of criminal records that may be used to assist law enforcement in apprehending fugitives. A law enforcement officer can submit a request to the NCIC during a traffic stop to determine whether the driver of the vehicle is wanted under an outstanding warrant or citation. However, NCIC inquiries frequently result in false positives that require the requesting officer to investigate further before any action can be taken. Consequently, because the NCIC system requires additional time and resources, it is inefficient for use in routine screening environments where large numbers of individuals need to be processed in a short amount of time.
The Computer-Assisted Passenger Prescreening System (CAPPS) is another example of an identity matching system that has been used to detect individuals who may pose a terrorist-related threat or who have outstanding Federal or state warrants for violent crimes. CAPPS assesses the identity of a passenger by matching passenger name information to government databases in order to determine if there is an exact (or near exact) name match. CAPPS relies on a simple matching algorithm to match the passenger's name with a name list. Matching algorithms that rely only upon a name are likely to generate a high number of false positives, such as publicized cases of Transportation Security Agency (TSA) employees stopping famous people or 2-year olds whose name happens to match the same name on a terrorist list.